Math 29 Homework #4

Frobenius confided to Dedekind how he sometimes tried to attain the goal
of proving a result by occupying himself with totally unrelated activities,
such as going with his wife to the trade exhibition, and then to the art exhibition,
by reading a novel at home, or else ridding his fruit trees of catepillars.
T. Y. Lam

Reading

Read what we covered in today's class: 2.3
Read what we will cover in the next class: 2.4

When reading 2.3 pay special attention to the following concepts:

  • substitution (composition), Theorem 2.3.1 (what does it say? why is this interesting?), rearrangement, identification and adding dummy variables to functions, Theorem 2.3.2 (what does it say? why is this interesting?).
When reading 2.4 pay special attention to the following concepts:
  • recursion, Theorem 2.4.2, look carefully at the examples in 2.4.3, Theorem 2.4.4 (what does it say? why is this interesting?).
    The rest of this section provides many specific examples of functions that are computable via recursion and, also, demonstrates that many common approaches mathematicians use for building functions preserve computability. Some important connections to decidabilty are also discussed. Read through this carefully and think of yourself as filling up your 'computability' toolbox with lots of good stuff...

Problems

The following problems are due by the beginning of class on Wednesday 4/7.
  • Define and give an example for each of the following:
    • recursion and recursion equations
  • Provide the formal details for Example 3.3 on page 31.
  • p. 32, # 2.3.4.1
  • p. 32, # 2.3.4.2
  • p. 32, # 2.3.4.3

Presentations

  • David, Theorem 2.3.1 on Monday 4/5
  • Joran, Theorem 2.4.4 on Wednesday 4/7
  • Amanda, Theorem 2.5.2 on Friday 4/9 (maybe Monday...)